Um, hasn't Frank said that he DOES still like puppeteering, and that basically, that's one of the main reasons he still dedicates at least one day out of the entire year to work on SST, simply for the fun and enjoyment of it?I've read/seen a lot of interviews with Frank, and it generally sounds like he's done being a puppeteer.
Not only that, but he HAS expressed interest, numerous, and multiple times, and that he would like to direct a theatrical Muppet movie, though he has said that Disney never approached him about directing.
As for not being sentimental about puppetry, I think that's more a reflection of how he and Jim thought so much alike, but Jim wasn't sentimental about puppetry either; yes, puppetry is what he did, and he poured so much of his heart and soul into all of the projects he did with puppetry, but it's not like each of these characters were like precious little bundles of joy to him. Caroll wrote of an anecdote in his memoir where one day, he was right-handing for Ernie, and when they cut the scene, Jim dropped Ernie to the floor to grab a prop, and as he walked back, simply nudged Ernie aside with his foot, so Caroll scooped him up and said, "Oh Ernie, it's okay, Jim didn't mean it", while Jim said, "Yes I did, he was in my way. Do you really talk to the puppets?" Caroll said whenever he dropped his puppets, like Picklepuss, his cat, he always apologized for doing so; Jim smiled at that, but explained that he wasn't sentimental about puppets, they were merely the tools he used in his line of work. Frank has said something very similar in the A&E special, he didn't refer to them as puppets, he refered to them as tools.